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• how to install Ubuntu on a fresh hard drive

  - by Herman Wiegman

  I attempted to install Ubuntu from a USB stick to my Intel 4 3GHz computer with 80GB HDD. The installer was doing well, then it said something to the effect of "errors on the source USB, or the target HDD" The recommendation was to download the installer again. I suspected my HDD was going bad so I figured I would investigate. What I found was a partially formatted 80GB HDD. I repartitioned it via a different computer. Now a fresh copy of the Ubuntu USB installer is not able to move past the start-up screen (it freezes). I was able to purchase a new / clean HDD, but still the fresh copy of the installer still locks up after the initial opening screen (locks up after about 2 screens worth of installations steps). Does this sounds like a HDD NTHS issue or a CPU/hardware/memory issue? or should I move to a CD image file rather than my USB stick? Now my computer is stuck... no OS.. no way to go back to Windows (upgrade OS CD only). Any insight would be greatly appreciated. Stuck in Schenectady Herman Wiegman

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• Is browser and bot whitelisting a practical approach?

  - by Sn3akyP3t3

  With blacklisting it takes plenty of time to monitor events to uncover undesirable behavior and then taking corrective action. I would like to avoid that daily drudgery if possible. I'm thinking whitelisting would be the answer, but I'm unsure if that is a wise approach due to the nature of deny all, allow only a few. Eventually someone out there will be blocked unintentionally is my fear. Even so, whitelisting would also block plenty of undesired traffic to pay per use items such as the Google Custom Search API as well as preserve bandwidth and my sanity. I'm not running Apache, but the idea would be the same I'm assuming. I would essentially be depending on the User Agent identifier to determine who is allowed to visit. I've tried to take into account for accessibility because some web browsers are more geared for those with disabilities although I'm not aware of any specific ones at the moment. The need to not depend on whitelisting alone to keep the site away from harm is fully understood. Other means to protect the site still need to be in place. I intend to have a honeypot, checkbox CAPTCHA, use of OWASP ESAPI, and blacklisting previous known bad IP addresses.

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• Question regarding Readability vs Processing Time

  - by Jordy

  I am creating a flowchart for a program with multiple sequential steps. Every step should be performed if the previous step is succesful. I use a c-based programming language so the lay-out would be something like this: METHOD 1: if(step_one_succeeded()) { if(step_two_succeeded()) { if(step_three_succeeded()) { //etc. etc. } } } If my program would have 15+ steps, the resulting code would be terribly unfriendly to read. So I changed my design and implemented a global errorcode that I keep passing by reference, make everything more readable. The resulting code would be something like this: METHOD 2: int _no_error = 0; step_one(_no_error); if(_no_error == 0) step_two(_no_error); if(_no_error == 0) step_three(_no_error); if(_no_error == 0) step_two(_no_error); The cyclomatic complexibility stays the same. Now let's say there are N number of steps. And let's assume that checking a condition is 1 clock long and performing a step doesn't take up time. The processing speed of Method1 can be anywhere between 1 and N. The processing speed of Method2 however is always equal to N-1. So Method1 will be faster most of the time. Which brings me to my question, is it bad practice to sacrifice time in order to make the code more readable? And why (not)?

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• Should we encourage coding styles in favor of developer's autonomy, or discourage it in favor of consistency?

  - by Saeed Neamati

  A developer writes if/else blocks with one-line code statements like: if (condition) // Do this one-line code else // Do this one-line code Another uses curly braces for all of them: if (condition) { // Do this one-line code } else { // Do this one-line code } A developer first instantiates an object, then uses it: HelperClass helper = new HelperClass(); helper.DoSomething(); Another developer instantiates and uses the object in one line: new HelperClass().DoSomething(); A developer is more easy with arrays, and for loops: string[] ordinals = new string[] {'First', 'Second', 'Third'}; for (i = 0; i < ordinals.Length; i++) { // Do something } Another writes: List<string> ordinals = new List<string>() {'First', 'Second', 'Third'}; foreach (string ordinal in ordinals) { // Do something } I'm sure that you know what I'm talking about. I call it coding style (cause I don't know what it's called). But whatever we call it, is it good or bad? Does encouraging it have an effect of higher productivity of developers? Should we ask developers to try to write code the way we tell them, so to make the whole system become style-consistent?

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• What technical details should a programmer of a web application consider before making the site public?

  - by Joel Coehoorn

  What things should a programmer implementing the technical details of a web application consider before making the site public? If Jeff Atwood can forget about HttpOnly cookies, sitemaps, and cross-site request forgeries all in the same site, what important thing could I be forgetting as well? I'm thinking about this from a web developer's perspective, such that someone else is creating the actual design and content for the site. So while usability and content may be more important than the platform, you the programmer have little say in that. What you do need to worry about is that your implementation of the platform is stable, performs well, is secure, and meets any other business goals (like not cost too much, take too long to build, and rank as well with Google as the content supports). Think of this from the perspective of a developer who's done some work for intranet-type applications in a fairly trusted environment, and is about to have his first shot and putting out a potentially popular site for the entire big bad world wide web. Also, I'm looking for something more specific than just a vague "web standards" response. I mean, HTML, JavaScript, and CSS over HTTP are pretty much a given, especially when I've already specified that you're a professional web developer. So going beyond that, Which standards? In what circumstances, and why? Provide a link to the standard's specification.

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• Is error suppression acceptable in role of logic mechanism?

  - by Rarst

  This came up in code review at work in context of PHP and @ operator. However I want to try keep this in more generic form, since few question about it I found on SO got bogged down in technical specifics. Accessing array field, which is not set, results in error message and is commonly handled by following logic (pseudo code): if field value is set output field value Code in question was doing it like: start ignoring errors output field value stop ignoring errors The reasoning for latter was that it's more compact and readable code in this specific case. I feel that those benefits do not justify misuse (IMO) of language mechanics. Is such code is being "clever" in a bad way? Is discarding possible error (for any reason) acceptable practice over explicitly handling it (even if that leads to more extensive and/or intensive code)? Is it acceptable for programming operators to cross boundaries of intended use (like in this case using error handling for controlling output)? Edit I wanted to keep it more generic, but specific code being discussed was like this: if ( isset($array['field']) ) { echo '<li>' . $array['field'] . '</li>'; } vs the following example: echo '<li>' . @$array['field'] . '</li>';

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• I receive the error 'grub-install /dev/sda failed' while attempting to install Ubuntu as the computer's only OS.

  - by Liath

  I am attempting to install Ubuntu on a box which was previously running Windows 7. I have also experienced the dreaded "Unable to install GRUB" error. I am not attempting to dual boot. I have previously run a Windows boot disk and removed all existing partitions. If I run the Ubuntu 12.04 install CD and click install after the config screens, I get the error Executing 'grub-install /dev/sda' failed. This is a fatal error. (It is the same error as this question: Unable to install GRUB) All the questions I've read while looking for a solution are related to dual boot. I'm not interested in dual boot, I'm after a clean out the box Ubuntu install. How can I achieve this? (For my sanity, please use very simple instructions when responding. I don't claim to have any talent either for linux or as a sysadmin) Additional details copied from comments dated: 2012-05-29 ~15:19Z After booting from the CD, clicking Try Ubuntu, and then sudo fdisk /dev/sda I get fdisk: unable to seek on /dev/sda: Invalid argument sudo fdisk /dev/sdb gives Device contains neither a valid DOS partiion table, nor Sun, SGI or OSF disklabel. Building a new DOS disklabel with disk identifier 0x15228d1d. Changes will remain in memory only until you decide to write them. After that of course, the previous content won't be recoverable. Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite). Command (m for help): I should add the Live CD desktop is graphically bad. I've got missing parts of programs and the terminal occasionally reflects to the bottom of the screen. But I can't imagine this is related.

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• Thoughts on exception handling.

  - by AndyScott

  Was working on a windows form app (something I haven't done in a while), adding threading and logging so that it would work a little more smoothly and have a record of who did what.  I was just about at the point where I was going to check it into source control when I noticed that the Output window was showing "A first chance exception of type 'System.InvalidCastException' occurred in mscorlib.dll", so I googled it.  In reading some threads about the error, I came across the following comment and it got me thinking: "In addition, while they should be avoided if possible, exceptions are a quite legitimate part of program execution. It's their going unhandled that is a real issue, because that means crashy, crashy." How do you normally use exception handling?  I feel that exceptions are intended to handle errors in code (in my experience generally related to bad data making its way into the system).  Now don't get me wrong, I understand that exceptions happen and should be dealt with, but I feel that they are a "last resort" to keep a program from crashing, but should never be a way to pass data or continue logical processing that could be handled in standard code flow. I mention this, because I have seen it done. What do you think?

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• How can I find out what site a popup ad came from?

  - by ændrük

  This is the situation: I've been browsing the web for an hour in pursuit of some bit of technical information and have visited several dozen websites that I don't even remember anymore. I've finally found what I need so I start closing the web browser, only to discover that — aaargh! — there's a popup ad hiding underneath! My blood boils. What insidious website is responsible for this circumvention of my browser's popup blocker? I want to make it pay for its crime. I'll write angry emails. Leave bad reviews. Even block it from my Google search results — yes, that'll show it! But I've reached an impediment. The offending site has already been closed. Is it too late to deduce the advertisement's origin? Or can I somehow un-pop the popup? Here's a test page. With only the popup left on your screen, can you deduce that it was caused by visiting PasteHTML?

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• How to sync client and server at the first frame

  - by wheelinlight

  I'm making a game where an authoritative server sends information to all clients about states and positions for objects in a 3d world. The player can control his character by clicking on the screen to set a destination for the character, much like in the Diablo series. I've read most information I can find online about interpolation, reconciliation, and general networking architecture (Valve's for instance). I think I understand everything but one thing seems to be missing in every article I read. Let say we have an interpolation delay of 100ms, server tickrate=50ms, latency=200ms; How do I know when 100ms has past on the client? If the server sends the first update on t=0, can I assume it arrives at t=200, therefore assuming that all packets takes the same amount of time to reach the client? What if the first packet arrives a little quick, for instance at t=150. I would then be starting the client with t=150 and at t=250 it will think it has past 100ms since its connect to the server when it in fact only 50ms has past. Hopefully the above paragraph is understandable. The summarized question would be: How do I know at what tick to start simulating the client? EDIT: This is how I ended up doing it: The client keeps a clock (approximately) in sync with the server. The client then simulates the world at simulationTime = syncedTime - avg(RTT)/2 - interpolationTime The round-trip time can fluctuate so therefore I average it out over time. By only keeping the most recent values when calculating the average I hope to adapt to more permanent changes in latency. It's still to early to draw any conclusion. I'm currently simulating bad network connections, but it's looking good so far. Anyone see any possible problems?

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• What should you do when presented with a horrible design?

  - by plua

  Our firm makes websites. We also design websites. But sometimes our client brings his/her own design. This is often made by an in-house designer, or it is the same design they used for something else. However, sometimes these designs look awful. And I am talking really unprofessional, unbalanced, uncool. But the client really wants this design. I really do not like working with a design that is so awful. It takes away all pleasure in coding. You code. You check the demo. Works great. Looks awful. It's just not fun. And ultimately the client might be happy, but 1) I do not feel proud of the final product and 2) the community sees you 'develop' ugly websites, which is bad for your image. Anybody experiencing this kind of stuff? What do you recommend? I've been thinking: Blocking these clients. If somebody has an 'own' design, ask to see it first. Then somehow politely decline. Drawback: you lose a client. Create a new design. Have our in-house designers work one something really cool. Drawbacks: client would need to pay for this (without asking for it), or it will be declined and the company loses time = money. And it might come as an insult if you propose a new design out of the blue. THEIR designer won't like it for sure. Put a clear disclaimer at the bottom of the site: Website design by XXXXX, Website development by US. Helps for the community-impact (if people pay attention), but not for the uneasy feeling.

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• ASP.NET design not SOLID

  - by w0051977

  SOLID principles are described here: http://en.wikipedia.org/wiki/SOLID_%28object-oriented_design%29 I am developing a large ASP.NET app. The previous developer created a few very large classes each with lots of different purposes. It is very difficult to maintain and extend. The classes are deployed to the web server along with the code behind files etc. I want to share a small amount of the app with another application. I am considering moving all of the classes of the ASP.NET web app to a DLL, so the small subset of functionality can be shared. I realise it would be better to only share the classes which contain code to be shared but because of the dependencies this is proving to be very difficult e.g. class A contains code that should be shared, however class A contains references to classes B, C, D, E, F, G etc, so class A cannot be shared on its own. I am planning to refactor the code in the future. As a temporary solution I am planning to convert all the classes into a single class library. Is this a bad idea and if so, is there an alternative? as I don't have time to refactor at the moment.

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• Faster 2D Collision detection

  - by eShredder

  Recently I've been working on a fast-paced 2d shooter and I came across a mighty problem. Collision detection. Sure, it is working, but it is very slow. My goal is: Have lots of enemies on screen and have them to not touch each other. All of the enemies are chasing the player entity. Most of them have the same speed so sooner or later they all end up taking the same space while chasing the player. This really drops the fun factor since, for the player, it looks like you are being chased by one enemy only. To prevent them to take the same space I added a collision detection (a very basic 2D detection, the only method I know of) which is. Enemy class update method Loop through all enemies (continue; if the loop points at this object) If enemy object intersects with this object Push enemy object away from this enemy object This works fine. As long as I only have <200 enemy entities that is. When I get closer to 300-350 enemy entities my frame rate begins to drop heavily. First I thought it was bad rendering so I removed their draw call. This did not help at all so of course I realised it was the update method. The only heavy part in their update method is this each-enemy-loops-through-every-enemy part. When I get closer to 300 enemies the game does a 90000 (300x300) step itteration. My my~ I'm sure there must be another way to aproach this collision detection. Though I have no idea how. The pages I find is about how to actually do the collision between two objects or how to check collision between an object and a tile. I already know those two things. tl;dr? How do I aproach collision detection between LOTS of entities? Quick edit: If it is to any help, I'm using C# XNA.

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• Being stupid to get better productivity?

  - by loki2302

  I've spent a lot of time reading different books about "good design", "design patterns", etc. I'm a big fan of the SOLID approach and every time I need to write a simple piece of code, I think about the future. So, if implementing a new feature or a bug fix requires just adding three lines of code like this: if(xxx) { doSomething(); } It doesn't mean I'll do it this way. If I feel like this piece of code is likely to become larger in the nearest future, I'll think of adding abstractions, moving this functionality somewhere else and so on. The goal I'm pursuing is keeping average complexity the same as it was before my changes. I believe, that from the code standpoint, it's quite a good idea - my code is never long enough, and it's quite easy to understand the meanings for different entities, like classes, methods, and relations between classes and objects. The problem is, it takes too much time, and I often feel like it would be better if I just implemented that feature "as is". It's just about "three lines of code" vs. "new interface + two classes to implement that interface". From a product standpoint (when we're talking about the result), the things I do are quite senseless. I know that if we're going to work on the next version, having good code is really great. But on the other side, the time you've spent to make your code "good" may have been spent for implementing a couple of useful features. I often feel very unsatisfied with my results - good code that only can do A is worse than bad code that can do A, B, C, and D. Are there any books, articles, blogs, or your ideas that may help with developing one's "being stupid" approach?

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• Ubuntu on Samsung NP700Z5B - no Grub

  - by copolii

  I just bought a Samsung NP700Z5B laptop. Gorgeous machine and great performance! I do 2 things when I get a new laptop: Format the HD and install Winblows from a CD to ditch the bloatware Install some variant of Linux on it (lately Ubuntu) Step 1 worked fine (until earlier today), but I haven't been able to install Ubuntu on it for the past 3 days! I've tried Mint12, Ubuntu 12.04, Ubuntu 11.10, Ubuntu 11.04 and Ubuntu 10.04. The live CD and the installations all run fine and report no problems, but when I reboot grub is nowhere to be found! The system goes directly to Winblows! I've tried booting from the liveCD and re-installing grub via the chroot and purge & reinstall methods (https://help.ubuntu.com/community/Grub2) and neither makes a difference. I've also tried copying the boot sector: dd if=/dev/sda of=linux.bin bs=512 count=1 and putting it on c: then setting bcdedit to add the entry to the Windows bootloader with no results. Earlier today I decided to try and set my boot partition as an EFI boot partition ... bad choice, now I don't even have the Winblows boot loader. I've officially ran out of ideas. Tried calling Samsung, but they're closed (they'd probably say something stupid along the lines of "Samsung recommends Windows 7" ... I've had Dell say that to me). Any help would be greatly appreciated. Update 1 Tried re-installing 12.04 and now I get the screen continously turning off and back on, but still no sign of booting ... it has been doing it for 15 mins so far (I set the boot partition type to ext2 instead of ext4) Update 2 Well ... this just gets better and better. I inserted the installation USB key to reboot it and the flickering stopped for about a minute (remained on) then it started turning off and on again

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• Have Windows Automatically Login Without Entering Your Password

  - by deadlydog

  If you are like me and don't want to have to enter your password each time Windows loads, you can have Windows start up without prompting you to enter a user name or password.  The simple (and BAD) way to do this is to simply not have a password on your user account, but that’s a big security risk and will allow people to easily remote desktop into your computer. So, first set a password on your windows account if you don’t already have one.  Then select Run... from the start menu (or use Windows Key + R to open the Run window) and type control userpasswords2, which will open the user accounts application.   On the Users tab, clear the box for Users must enter a user name and password to use this computer, and click on OK. An Automatically Log On dialog box will appear; enter the user name and password for the account you want to use to automatically log into Windows.  That's it.    You may also want to make sure your screen saver is not set to prompt you for a password when it exits either. Now your computer is secure without getting in your way.

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• Is there any way to send a column value from outer query to inner sub query? [closed]

  - by chetan

  'Discussions' table schema title description desid replyto upvote downvote views browser used a1 none 1 1 12 - bad topic b2 a1 2 3 14 sql database a3 none 4 5 34 - crome b4 a3 3 4 12 The above table has two types of content types Main Topics and Comments. Unique content identifier 'desid' used to identify that its a main topic or a comment. 'desid' starts with 'a' for Main Topic and for comment 'desid' starts with 'b'. For comment 'replyto' is the 'desid' of main topic to which this comment is associated. I like to find out the list of the top main topics that are arranged on the basis of (upvote+downvote+visits+number of comments to it) addition. The following query gives top topics list in order of (upvote+downvote+visits) select * with highest number of upvote+downvote+views by query "select * from [DB_user1212].[dbo].[discussions] where desid like 'a%' order by (upvote+downvote+visited) desc For (comments+upvote+downvote+views ) I tried select * from [DB_user1212].[dbo].[discussions] where desid like 'a%' order by ((select count(*) from [DB_user1212].[dbo].[discussions] where replyto = desid )+upvote+downvote+visited) desc but it didn't work because its not possible to send desid from outer query to inner subquery. How to solve this? Please note that I want solution in query language only.

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• Learning a new concept - write from scratch or use frameworks?

  - by Stu

  I have recently been trying to learn about MVVM and all of the associated concepts such as repositories, mediators, data access. I made a decision that I would not use any frameworks for this so that I could gain a better understanding of how everything worked. I’m beginning to wonder if that was the best idea because I have hit some problems which I am not able to solve, even with the help of Stack Overflow! Writing from scratch I still feel that you have a much better understanding of something when you have been in the guts of it than if you were at a higher level. The other side of that coin is that you are in the guts of something that you don't fully understand which will lead to bad design decisions. This then makes it hard to get help because you will create unusual scenarios which are less likely to occur when you working within the confines of a framework. I have found that there are plenty of tutorials on the basics of a concept but very few that take you all the way from novice to expert. Maybe I should be looking at a book for this? Using frameworks The biggest motivation for me to use frameworks is that they are much more likely to be used in the workplace than a custom rolled solution. This can be quite a benefit when starting a new job if it's one less thing you have to learn. I feel that there is much better support for a framework than a custom solution which makes sense; many more people are using the framework than the solution that you created. The level of help is much wider as well, from basic questions to really specific, detailed questions. I would be interested to hear other people's views on this. When you are learning something new, should you/do you use frameworks or not? Why? If it's a combination of both, when do you stop one and move on to the other?

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• X won't start, root filesystem mounted read only

  - by TK Kocheran

  I just experienced a very strange and puzzling problem on my machine that I can't seem to get sorted out. I was running Windows on a second partition, and everything was working great. I then went to restart into Linux, and noticed that X wouldn't start. Everything was displayed in super-low resolution, so I tried reinstalling my NVIDIA driver. I started seeing all of these I/O error problems, so I figured that my SSD was bad. After a bit more playing around, I ran fsck on the drive when mounted from a startup disk as well as badsectors and everything looked great. The SMART drive tests all passed and again, everything was looking good, so I rebooted again and still, no joy. I started then getting some weird USB errors, so I followed someone's advice and unplugged my computer's power supply, then started back up again and my graphics looked a lot better in the BIOS and in the boot logo, but X still wouldn't start. I then found out that my main boot drive was being mounted read-only for some reason. What's going wrong? I've done some pretty extensive tests on the SSD from a startup disk such as writing massive files, reading big files, running filesystem checks on the entire disk, and everything is looking great, until I try to boot. Whenever I try installing the drivers with apt-get, I get a ton of ata error messages looking like this: How can I diagnose what's going wrong and fix it so I can get back to work?

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• How to mount private network shares on login?

  - by bainorama

  I've read all the existing entries I could find on using pam_mount but none of them seem to work for me. I'm trying to automatically mount shares on my local NAS at user login time. The usernames and passwords on my NAS shares match my local user name and password, but there is no LDAP/AD server. My pam_mount.conf has the following: <volume fstype="cifs" server="bain-brain" path="movies" user="*" sgrp="bains" mountpoint="/home/%(USER)/movies" options="user=%(USER),dir_mode=0700,file_mode=700,nosuid,nodev" /> When I login, I see the following in /var/log/auth.log: Oct 13 10:21:26 bad-lattitude lightdm: pam_mount(misc.c:380): 29 20 0:20 / /home/alastairb/movies rw,nosuid,nodev,relatime - cifs //bain-brain/movies rw,sec=ntlm,unc=\\bain-brain\movies,username=alastairb,uid=1000,forceuid,gid=1000,forcegid,addr=10.1.1.12,file_mode=01274,dir_mode=0700,nounix,serverino,rsize=61440,wsize=65536,actimeo=1 The folder /home/alastairb/movies is present but empty (can't see the files which are on the NAS in the respective share folder). In Nautilus, the share is shown in the sidebar under "Computer", and clicking on this takes me to the correct folder, but again, its empty. Any ideas as to what I'm doing wrong?

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• Wireless connection disconnects and reconnects with a Netgear WNA1000

  - by William Berkenkamp

  Ever since I made the permanent switch from Vista to Ubuntu i've had wireless connectivity problems. From watching the network manager when it disconnects it seems like it turns off the receiver for some reason. Could it be bad drivers? I used their install software and the site doesn't really offer driver downloads. The adapter is a Netgear WNA1000 if memory serves, and I don't know much about the router except that it's a Motorola Surfboard. And I figure this might help a bit *-network description: Ethernet interface product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:01:00.0 logical name: eth0 version: 01 serial: 00:1b:b9:a7:39:a4 size: 10Mbit/s capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm vpd msi pciexpress bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=N/A latency=0 link=no multicast=yes port=MII speed=10Mbit/s resources: irq:40 ioport:d800(size=256) memory:feaff000-feafffff memory:feac0000-feadffff *-network description: Wireless interface physical id: 1 bus info: usb@2:1.1 logical name: wlan0 serial: 00:26:f2:8b:fb:38 capabilities: ethernet physical wireless configuration: broadcast=yes driver=carl9170 driverversion=3.2.0-24-generic-pae firmware=1.9.4 ip=10.0.0.36 link=yes multicast=yes wireless=IEEE 802.11bgn I have tried installing WICD and it didn't fix the problem. Any help would be greatly appreciated. This problem is greatly limiting what I can do with my computer.

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• Rails: The Law of Demeter [duplicate]

  - by user2158382

  This question already has an answer here: Rails: Law of Demeter Confusion 4 answers I am reading a book called Rails AntiPatterns and they talk about using delegation to to avoid breaking the Law of Demeter. Here is their prime example: They believe that calling something like this in the controller is bad (and I agree) @street = @invoice.customer.address.street Their proposed solution is to do the following: class Customer has_one :address belongs_to :invoice def street address.street end end class Invoice has_one :customer def customer_street customer.street end end @street = @invoice.customer_street They are stating that since you only use one dot, you are not breaking the Law of Demeter here. I think this is incorrect, because you are still going through customer to go through address to get the invoice's street. I primarily got this idea from a blog post I read: http://www.dan-manges.com/blog/37 In the blog post the prime example is class Wallet attr_accessor :cash end class Customer has_one :wallet # attribute delegation def cash @wallet.cash end end class Paperboy def collect_money(customer, due_amount) if customer.cash < due_ammount raise InsufficientFundsError else customer.cash -= due_amount @collected_amount += due_amount end end end The blog post states that although there is only one dot customer.cash instead of customer.wallet.cash, this code still violates the Law of Demeter. Now in the Paperboy collect_money method, we don't have two dots, we just have one in "customer.cash". Has this delegation solved our problem? Not at all. If we look at the behavior, a paperboy is still reaching directly into a customer's wallet to get cash out. EDIT I completely understand and agree that this is still a violation and I need to create a method in Wallet called withdraw that handles the payment for me and that I should call that method inside the Customer class. What I don't get is that according to this process, my first example still violates the Law of Demeter because Invoice is still reaching directly into Customer to get the street. Can somebody help me clear the confusion. I have been searching for the past 2 days trying to let this topic sink in, but it is still confusing.

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• Is learning C# as a first language a mistake?

  - by JuniorDeveloper1208

  I know there are similar questions on here, which I've read, but I recently read this post by Joel Spolsky: How can I teach a bright person, with no programming experience, how to program? And it got me thinking about my way of learning and whether it might actually be harmful in the long run. I've dabbled with various languages but C# is my first serious one, I've read "Head First C#" and created a few projects. But after reading the post above I've found it a bit disheartening that I may be going about it all wrong, obviously I respect Joel's opinion which is what has thrown me a bit. I've started reading "Code" as recommended in the reading list and I'm finding it pretty hard going, although enjoyable. I feel like it's taken the shine off of my "noobish hacking about" in Visual Studio. So now I'm unsure as to what path I should take? Should I take a step back and follow Joel's advice and start reading? I guess my main aim is just to become a good programmer, like everyone else, but I don't want to be going into bad practice by learning a .NET language when someone who's opinion I respect thinks that it is harmful. Thoughts?

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• unable remove/reinstall libxss1:amd

  - by mono

  Whenever I try to install anything (software-center or apt-get) I get an error report stating that libxss1:amd is in a "very bad inconsistent state" (translated from german) and that I should reinstall it. That would not bother me much but I am never sure if the stuff I'm trying will be working in the end. It really resists from being repaired apt-get install, apt-get remove, apt-get -f install, and all the usual suspects - nothing works. It always comes to: dpkg: Fehler beim Bearbeiten von libxss1:amd64 (--configure): Paket ist in einem sehr schlechten inkonsistenten Zustand - Sie sollten es nochmal installieren, bevor Sie die Konfiguration versuchen. Fehler traten auf beim Bearbeiten von: libxss1:amd64 E: Sub-process /usr/bin/dpkg returned an error code (1) I posted the error as is, since my translation might not be exact. But I guess you can figure from my text. I found out that this file is the X screen saver. Maybe I should kill it before handling that file. If thats so, than please tell me how. Thanks for your help, thomas

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• I have discovered a fundamental truth about TV shows and plots

  - by Steve Loethen

  For years, we have all known (okay, maybe I give people too much credit) that there is a very small finite number of plots.  I propose a project.  Let’s use the blogosphere to catalog those plotlines, and then find and document the episodes of shows that use them, including the show title. As evidence, how many shows have used the following plot line:? The standard “evil twin” plotline?  Once relegated to soaps, it has show up in crime shows, with the twist of DNA.  Step one, concentrate one this one.  Tell me about every show you recall that has used this plot.  I will collect and document the shows on my website (www.loethen.net) and we can build a database of the plots. Step two, what other common themes should I offer up?  How about the bigamist plot line?  The “bad guy was dead” plot line (revenge from the dead"?  The “vast government conspiracy” plotline? Let the games begin….

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